feat(profile): avatar presets, upload, nickname editing

- FastAPI: preset assets 01–08, GET list/static, PUT /me/avatar/preset,
  safer uploaded-avatar path validation, preset_avatars + HTTP tests.
- Expo: personal-info (library + presets), profile tab avatar,
  resolveApiMediaUrl, auth hooks cache sync, Web multipart helper,
  partial-save messaging + profile i18n.
- Includes existing edits to conversation screen and voice use-player.

Co-authored-by: Cursor <cursoragent@cursor.com>

app-expo/src/app/(tabs)/profile.tsx

@@ -1,4 +1,5 @@
 import { router } from 'expo-router';
+import { Image } from 'expo-image';
 import React from 'react';
 import { Pressable, ScrollView, View } from 'react-native';
 import { useTranslation } from 'react-i18next';
@@ -21,6 +22,7 @@ import {
 import { Icon } from '@/components/ui/icon';
 import { Switch } from '@/components/ui/switch';
 import { Text } from '@/components/ui/text';
+import { resolveApiMediaUrl } from '@/core/api/media-url';
 import { useAppSettings } from '@/hooks/use-app-settings';
 import { useSession, useLogout } from '@/features/auth/hooks';
 import { useCurrentPlan } from '@/features/profile/hooks';
@@ -181,6 +183,8 @@ export default function ProfileScreen() {
     themeOptions.find((o) => o.value === themeName)?.label ??
     tApp('theme.default');
 
+  const avatarUri = resolveApiMediaUrl(user?.avatar_url ?? null);
+
   return (
     <ScrollView
       contentInsetAdjustmentBehavior="automatic"
@@ -191,10 +195,19 @@ export default function ProfileScreen() {
       <View className="items-center gap-4 py-8">
         <View className="relative">
           <View
-            className="h-24 w-24 items-center justify-center rounded-full bg-muted"
+            className="h-24 w-24 items-center justify-center overflow-hidden rounded-full bg-muted"
             style={{ borderCurve: 'continuous' }}
           >
-            <Icon as={User} className="text-muted-foreground" size={40} />
+            {avatarUri ? (
+              <Image
+                source={{ uri: avatarUri }}
+                style={{ width: '100%', height: '100%' }}
+                contentFit="cover"
+                accessibilityIgnoresInvertColors
+              />
+            ) : (
+              <Icon as={User} className="text-muted-foreground" size={40} />
+            )}
           </View>
           <Pressable
             className="absolute bottom-0 right-0 h-9 w-9 items-center justify-center rounded-full border-2 border-background bg-primary"